Conventionally, a cell analyzer is known for analyzing cells contained in biological samples collected from a living body. For example, US Pub. No. 2008/108103 discloses a cell analyzer which determines the progression of canceration based on measurement results obtained by using a flow cytometer to measure epithelial cells contained in a sample collected from the cervix of a subject.
In this cell analyzer, it is preferable to use a large number of cells to be analyzed to increase the accuracy of analysis when performing analysis of individual cells. For example, US Pub. No. 2011/076755 discloses a sample preparation apparatus which is capable of increasing the number of cells per unit volume supplied for analysis by increasing the concentration of the cells contained in a sample.
This sample preparation apparatus has a storage chamber for accommodating a sample when the top surface is opened, a cylindrical piston which has a filter loaded at the bottom end surface and which is inserted into the storage chamber, a suction tube for suctioning a liquid that penetrates to the interior of the piston through the filter, and a stirrer disposed at the bottom of the storage chamber. In the process of concentrating the sample, the sample is first charged into the storage chamber. Thereafter, the piston is inserted in the storage chamber until the filter is immersed in the sample. At this time, the liquid leaking into the piston is suctioned by the suction tube and then removed from the storage chamber. The cells to be analyzed adhere to the bottom surface of the filter and do not pass through the filter. The cells adhered to the bottom surface of the filter are detached from the filter by operating the stirrer, if appropriate. The sample remaining in the storage chamber now contains a high concentration of cells to be analyzed.
In order to make replacement of the filter easy, it is contemplated that the filter is attached to a holding member, and then the member is detached from the apparatus.